[rocky]

https://flic.kr/p/WVFGfS

Any help is appreciated. This is the 6th time I'm doing this job. The bolts for the fan belt tensioner mount keep breaking. I'm out of ideas. I have replaced everything. I've tried different grade bolts and even studs. I think the problem is with the metal surface you can see breaking away at the 2 bolt holes. If that's the case it will require a new engine as it is part of the block and not a cover. Any ideas or advice? The fan hub turns freely and is working properly. That's all this belt runs.

[trackbird]

The bolts appear to be cracking from fatigue. To my eye, they look to be starting to crack on the "bottom" and the last bit of failure is the top section of each bolt (at about 10:30). Replace them with something from ARP? Are the bolts shanked bolts? Or fully threaded? If they are shanked, are they breaking at the last thread or are there threads left on the section that's not stuck in the block? Are they staying tight? If they were to start to come loose, then the belt flopping/vibrating the mount could start to fatigue crack the bolts.